Electronic apparatuses such as cellular phones may be mounted with a plurality of microphones. For instance, a cellular phone may be provided with a microphone for detecting ambient sound (environmental sound) for a purpose of noise canceling in addition to a microphone for detecting a transmission voice during a call. As more and more electronic apparatuses are mounted with a plurality of microphones, downsizing of microphones is increasingly demanded.
Against a background like this, in recent years, a microphone manufactured using a micro electro mechanical systems (MEMS) technology (hereinafter, referred to as a MEMS microphone) has been drawing an attention (for instance, Patent Publication JP 2004-506394 A).
In mounting a microphone onto an electronic apparatus, not only downsizing of a microphone but also sensitivity enhancement of the microphone is required. Sensitivity enhancement is required also for a MEMS microphone.